Are blood diamonds making a comeback?

They look pretty, don't they? It turns out that these raw diamonds were mined in the Democratic Republic of the Congo in the midst of a rebel uprising. See more diamond pictures.
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In the 2006 movie "Blood Diamond," Leonardo DiCaprio plays a morally questionable diamond smuggler in war-ravaged Sierra Leone. Although the plotline is pure fiction, the movie is based on real events. In the 1990s, a rebel organization called the Revolutionary United Front (RUF) spread a reign of terror across diamond mining villages in Sierra Leone.

The RUF committed brutal acts of torture, rape and murder to intimidate the citizens of Sierra Leone and take control of the country's diamond mines. Tens of thousands were killed and tens of thousands more lost limbs to the rebels. Young boys were forcibly recruited and brainwashed to work for roving death squads.

Meanwhile, some of the diamonds that were mined by slave labor in Sierra Leone were smuggled to neighboring countries and sold to international diamond traders, who either didn't know the source of the jewels or turned a blind eye to their blood-soaked origins.

Rebel armies in the Democratic Republic of Congo and Angola also used diamonds to fund their wars [source: PBS Online NewsHour]. In the late 1990s, an estimated 15 percent of the world's rough diamond production came from regions in conflict [source: PAC].

So-called "conflict diamonds" or "blood diamonds" first came to international attention in the late 1990s via outcry from human rights organizations and the media. In May 2000, several major African diamond-producing countries met in Kimberley, South Africa, to collectively address the controversy. That December, the United Nations passed a resolution supporting the creation of an international diamond certification process that would keep blood diamonds off the market.

In November 2002, a coalition of diamond-producing nations, diamond industry representatives and non-governmental organizations (NGOs) drafted the Kimberley Process Certification Scheme (KPCS), a framework designed to regulate the international rough diamond trade. Seventy-five countries joined the Kimberley Process -- the shortened name for the KPCS -- and vowed to set and follow standards that would prevent the illicit trade of conflict diamonds.

Seven years later, critics of the Kimberley Process question whether the KPCS regulations have had any real effect on the flow of illicit diamonds from conflict regions. Partnership Africa Canada (PAC), an NGO that helped draft the KPCS, believes that 20 percent of the world's rough diamond trade is still unregulated and unmonitored [source: PAC].

What does the KPCS require and which countries are defying its efforts? Read on to learn more about the possible return of blood diamonds.